Apodized Lyot Coronagraph for VLT-SPHERE: Laboratory tests and performances of a first prototype in the visible

Géraldine Guerri (1) , Sylvie Robbe-Dubois (1) , Jean-Baptiste Daban (1) , Lyu Abe (1) , Richard Douet (1) , Philippe Bendjoya (1) , Farrokh Vakili (1) , Marcel Carbillet (1) , Jean-Luc Beuzit (2) , Pascal Puget (2) , Kjetil Dohlen (3) , David Mouillet (2)

1 FIZEAU - Laboratoire Hippolyte Fizeau
2 LAOG - Laboratoire d'Astrophysique de Grenoble
3 LAM - Laboratoire d'Astrophysique de Marseille

We present some of the High Dynamic Range Imaging activities developed around the coronagraphic test-bench of the Laboratoire A. H. Fizeau (Nice). They concern research and development of an Apodized Lyot Coronagraph (ALC) for the VLT-SPHERE instrument and experimental results from our testbed working in the visible domain. We determined by numerical simulations the specifications of the apodizing filter and searched the best technological process to manufacture it. We present the results of the experimental tests on the first apodizer prototype in the visible and the resulting ALC nulling performances. The tests concern particularly the apodizer characterization (average transmission radial profile, global reflectivity and transmittivity in the visible), ALC nulling performances compared with expectations, sensitivity of the ALC performances to misalignments of its components.

Mots clés: High contrast imaging; Astronomical Instrumentation: Coronagraphy

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Astrophysique [astro-ph]

Géraldine Guerri, Sylvie Robbe-Dubois, Jean-Baptiste Daban, Lyu Abe, Richard Douet, et al.. Apodized Lyot Coronagraph for VLT-SPHERE: Laboratory tests and performances of a first prototype in the visible. Astronomical Telescopes and Instrumentation, Jun 2008, Marseille, France. pp.70143J-(1-12). ⟨hal-00346699⟩